Rift Valley fever (RVF), a viral disease endemic throughout Africa, frequently causes severe ocular sequelae in humans. Infection of inbred rats, Rattus norvegicus, has been shown to mimic several of the clinical manifestations of the human disease. For clinical study of this disease, a restraint device was needed which would allow large numbers of unanesthetized, infected rats to be easily screened by one individual.
Currently, there are no commercially available restraint devices that are suitable for ophthalmic examination of unanesthetized rats. Most restraint devices are designed for administering inoculations or studies involving physiological or behavioral measurements. One device which would allow ophthalmic examinations is described in H. C. Ebel, "A Restraining Device for Use in the Measurement of Eyelid Responses in Laboratory Rats," J. Exp Anal. Behav. (1966) 9:605-606. However, this device is cumbersome and requires the rats to be lightly anesthetized.
Several U.S. Patents disclose restraint device devices for small animals. U.S. Pat. No. 2,987,042 (Rothberg) discloses a hollow device having a concave upper surface. The animal is straddled over the concave surfaces and is strapped to the outer surface of this device.
U.S. Pat. No. 3,094,101 (Porter) discloses a restraining device for small animals comprising an elongated cage portion having side walls provided with slide guides for supporting a longitudinally slidable and vertically adjustable floor member. A vertically adjustable end wall is provided with a tail holder for preventing the movement of the specimen's tail.
U.S. Pat. No. 3,428,030 (Updegraff) discloses a restraining device which allows an individual to provide an intravenous injection to the specimen.
U.S. Pat. No. 3,474,763 (Kiss et al.) discloses a restraining device which allow the specimen's legs and tail to be exposed. This device fails to provide any means for observing the eyes of the specimen.
U.S. Pat. No. 3,625,185 (Kenter) discloses a restraining device having an adjustable cylindrical section, a gate at one end of the cylinder, and a variable closure at the other end of the cylinder.
A major disadvantage of the restraints described above is that the restraints do not, in general, permit a researcher to quickly and easily observe the eyes of unanesthetized animal. Further, in some instances, the restraint devices are unsuitable for ophthalmic examination, since the eyes of the animal are covered or otherwise made inaccessible by the restraint device itself.